German Patent DE 100 53 232 discloses a substrate delivery module for a workstation. Semiconductor substrates are transferred out of the substrate delivery module to the workstation for further examination. In the workstation, for example, microscopic examinations of the semiconductor substrate are performed. The system made up of the substrate delivery module and workstation is particularly flexible, since the substrate delivery module can be mounted on any side of the workstation. The apparatus described in the patent has the critical disadvantage, however, that only one specific operation—for example, a macroinspection or microinspection—can be performed in the workstation. If more than one examination is to be performed with the workstation, this requires an additional device; this increases the basal area or installation area of the overall apparatus at a semiconductor fabrication site.
In the manufacture of semiconductor wafers, between certain manufacturing steps the substrates are transported in cassettes of various kinds to different workstations, and there must be introduced into the respective workstation. Transport can be accomplished manually or automatically.
Each of the workstations serves different purposes for treatment of the substrates, such as inspection, measurement or processing of the substrates. In terms of inspection of the substrates, a distinction is made between a macroinspection and a microinspection. An inspection is performed in the latter case, in particular, in terms of undesirable particles on the substrates, or defects in the features or on the surface of the substrate. The inspection can be accomplished by the user him- or herself, or automatically using an electronic camera. For example, the undesirable particles or feature defects can be automatically recognized and classified (defect analysis). In addition, the widths or thicknesses of the features can be measured (CD analysis, layer thickness analysis). Because of the small size of the objects being examined on the substrate, microscopes are usually used in such workstations for this inspection and assessment application. Macroinspection is performed in a separate workstation. In macroinspection, macroscopic defects such as scratches, coating defects or dirt particles, or other macroscopic inhomogeneities such as fluctuations in the thickness of thin layers applied to the semiconductor substrate, can be rapidly detected. These defects can thus be passed on to a microinspection step for more thorough inspection.